Before revision:  The stochastic dynamic origin of the long-term mean and instantaneous volatility of the Vasicek model have been explained. Despite the lack of normality of probability distributions involved,  newly elaborated models have the same degree of analytical tractability as the Black--Scholes model and the Vasicek model .
After revision:  The stochastic dynamic origin of the long-term mean and instantaneous volatility of the Vasicek model has been uncovered. A generalized bond pricing model has been introduced and developed based on short term interest rate stochastic dynamics modeled by superposition of a standard Wiener process and shot noise. Despite the non-Gaussianity of probability distributions involved, newly elaborated models have the same degree of analytical tractability as the Black--Scholes model and the Vasicek model .